The present invention relates to a housing for a small electrical machine, particularly a small electric motor with permanent magnets, and a method of manufacturing the same.
Housings for small electrical motors, having a cylindrical wall, are known. The cylindrical wall of a known housing is constituted by a sheet-metal band which is bent and has a thickness not exceeding 3 mm. A Sendzimir-zink-plated iron sheet is utilized for manufacturing such the band. The thus-produced cylindrical wall has the advantage that it possesses high corrosion-resistance characteristics. The cut off edges of the band are reliably protected against corrosion by the cathodic protective action. However, in the electric motors having great power, the cylindrical wall which forms a part of the magnetic circuit of the motor must have a thickness which exceeds the above-mentioned maximum thickness of the iron sheet. When it is necessary to provide the cylindrical wall forming a part of the magnetic circuit, with a thickness exceeding 4 mm, then the cylindrical wall must be manufactured from a plain not zink-coated sheet iron which is subsequently galvanically coated with zinc. Such a process is expensive and complicated. Moreover, in order to manufacture such thick iron sheet large and powerful processing machines are required.